Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.4.2.30 (PARP)
13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of cyclic AMP (cAMP)-dependent phosphorylation and ADP-ribosylation on the activities of the rat liver bifunctional enzyme, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2/FBPase-2), was investigated in order to determine the role of the N-terminus in covalent modification of the enzyme. The bifunctional enzyme was demonstrated to be a substrate in vitro for arginine-specific ADP-ribosyltransferase: 2 mol of ADP-ribose was incorporated per mol of subunit. The Km values for NAD+ and PFK-2/FBPase-2 were 14 microM and 0.4 microM respectively. A synthetic peptide (Val-Leu-Gln-Arg-Arg-Arg-Gly-Ser-Ser-Ile-Pro-Gln) corresponding to the site phosphorylated by cAMP-dependent protein kinase was ADP-ribosylated on all three arginine residues. Analysis of ADP-ribosylation of analogue peptides containing only two arginine residues, with the third replaced by alanine, revealed that ADP-ribosylation occurred predominantly on the two most C-terminal arginine residues. Sequencing of the ADP-ribosylated native enzyme also demonstrated that the preferred sites were at Arg-29 and Arg-30, which are just N-terminal to Ser-32, whose phosphorylation is catalysed by cAMP-dependent protein kinase (PKA). ADP-ribosylation was independent of the phosphorylation state of the enzyme. Furthermore, ADP-ribosylation of the enzyme decreased its recognition by liver-specific anti-bifunctional-enzyme antibodies directed to its unique N-terminal region. ADP-ribosylation of PFK-2/FBPase-2 blocked its phosphorylation by PKA, and decreased its PFK-2 activity, but did not alter FBPase-2 activity. In contrast, cAMP-dependent phosphorylation inhibited the kinase and activated the bisphosphatase. These results demonstrate that ADP-ribosylation of arginine residues just N-terminal to the site phosphorylated by PKA modulate PFK-2 activity by an electrostatic and/or steric mechanism which does not involved uncoupling of N- and C-terminal interactions as seen with cAMP-dependent phosphorylation.
...
PMID:Role of the N-terminal region in covalent modification of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase: comparison of phosphorylation and ADP-ribosylation. 761 45

We reported previously on ADP-ribosylation of actins by chicken arginine-specific ADP-ribosyltransferase in vitro and in situ and the inhibition of actin polymerization by this modification [Terashima, M., Mishima, K., Yamada, K., Tsuchiya, M., Wakutani, T. & Shimoyama, M. (1992) Eur. J. Biochem. 204, 305-311]. In the present study, we determined amino acid residues of ADP-ribosylation site(s) in globular (G-) and filamentous (F-) actins and examined the molecular basis of the modification of actin. Arginine-specific ADP-ribosylation occurred at Arg28 and Arg206 in G-actin, but only at Arg28 in F-actin. ADP-ribosylation of Arg206, located on the pointed end of the actin molecule, significantly blocked the interaction with deoxyribonuclease I. These results indicate that Arg206 in G-actin may be involved in actin polymerization. ADP-ribosylation of Arg28, located on the outer surface of actin molecule, did not affect the binding activity with myosin subfragment-1, that is thought to interact through the N-terminal amino acid residues of G-actin. ADP-ribosylation at both Arg28 and Arg206 of G-actin had no apparent effect on the intrinsic ATPase activity. We concluded from this study that ADP-ribosylation of Arg206 in G-actin causes the inhibition of actin polymerization, and that ADP-ribosylation of Arg28 occurs in F-actin.
...
PMID:ADP-ribosylation of Arg28 and Arg206 on the actin molecule by chicken arginine-specific ADP-ribosyltransferase. 762 77

Triton X-114 phase partitioning, a procedure used for purifying integral membrane proteins, was used to study protein components of the mammalian visual transduction cascade. An integral membrane protein, rhodopsin, and two isoprenylated protein complexes, cyclic GMP phosphodiesterase and Gt beta gamma, partitioned into the detergent-rich phase. Arrestin, a soluble protein, accumulated in the aqueous phase. Gt alpha distributed about equally between phases whether GDP (Gt alpha.GDP) or GTP (Gt alpha.GTP) was bound. Gt beta gamma increased recovery of Gt alpha.GDP but not Gt alpha.GTP in the detergent phase. Trypsin-treated Gt alpha, which lacks the fatty acylated amino-terminal 2-kDa region, accumulated to a greater extent in the aqueous phase than did intact Gt alpha. Trypsinized cGMP phosphodiesterase, which lacks the isoprenyl group, partitioned into the aqueous phase. A carboxyl-terminal truncated mutant (Val-331 stop) of Gt alpha accumulated more in the aqueous phase then did recombinant full-length Gt alpha, supporting the role of the carboxyl terminus in increasing its hydrophobicity. N-Myristoylated recombinant Go alpha was more hydrophobic than recombinant Go alpha without myristate. ADP-ribosylation of Gt alpha catalyzed by NAD:arginine ADP-ribosyltransferase, but not by pertussis toxin, increased hydrophilicity. Triton X-114 phase partitioning can thus semiquantify the hydrophobic nature of proteins and protein domains. It may aid in evaluating changes associated with post-translational protein modification and protein-protein interactions in a defined system.
...
PMID:Hydrophobicity and subunit interactions of rod outer segment proteins investigated using Triton X-114 phase partitioning. 762 4

Integrin alpha 7 is a major substrate in skeletal muscle cells for the cell surface, glycosylphosphatidylinositol-anchored, arginine-specific ADP-ribosyltransferase. Since ADP-ribosylarginine hydrolase, the enzyme responsible for cleavage of the ADP-ribosylarginine bond and a component with the transferase of a putative ADP-ribosylation cycle, is cytosolic, the processing of ADP-ribosylated integrin alpha 7 was investigated. Following incubation of differentiated mouse C2C12 myoblasts with [adenylate-32P]NAD and analysis by SDS-polyacrylamide gel electrophoresis under reducing conditions, two [32P]ADP-ribosylated forms of integrin alpha 7 were resolved. By pulse-chase and purification of the radiolabeled proteins on a laminin affinity column, it was demonstrated that a 105-kDa ADP-ribosylated form originated from a mono-ADP-ribosylated 102-kDa form and represented integrin alpha 7 modified at more than one site. The additional site(s) of modification, utilized at higher NAD concentrations, were located in the 63-kDa N-terminal segment of integrin alpha 7. Both [32P]ADP-ribosylated integrins were loosely associated with the cytoskeleton, bound to laminin affinity columns, and immunoprecipitated with antibodies to integrin beta 1. 32P label was rapidly removed from [32P]ADP-ribosylated integrin alpha 7 at either site of modification, a process inhibited by free ADP-ribose or p-nitrophenylthymidine-5'-monophosphate, an alternative substrate of 5'-nucleotide phosphodiesterase. The processed integrin alpha 7 was unavailable for subsequent ADP-ribosylation, although the amount of surface integrin alpha 7 remained constant. During the processing, no loss of label was observed from integrin alpha 7 radiolabeled with [14C]NAD, containing 14C in the nicotinamide proximal ribose, consistent with degradation of the ADP-ribose moiety by a cell surface 5'-nucleotide phosphodiesterase. Thus, cell surface ADP-ribosylation, in contrast to intracellular ADP-ribosylation, is not readily reversed by ADP-ribosylarginine hydrolase and seems to operate outside the postulated ADP-ribosylation cycle.
...
PMID:Processing of ADP-ribosylated integrin alpha 7 in skeletal muscle myotubes. 772 41

Using high-voltage capillary electrophoresis we detected ADP-ribosylarginine, a product of ADP-ribosylation reaction catalyzed by arginine-specific ADP-ribosyltransferase in the presence of NAD and L-arginine. The authentic ADP-ribosylarginine, detected by its ultraviolet absorbance at 254 nm, had a different retention time from NAD or nicotinamide. When the ADP-ribosylation reaction products were analyzed, the peak corresponding to ADP-ribosylarginine increased with incubation time and in an enzyme-dose-dependent manner. The lower limit of detection was 0.3 pmol, a value 100 times lower than that obtained with the reversed-phase high-performance liquid chromatography assay described previously. Using the capillary electrophoresis system, a thiol-independent ADP-ribosyltransferase activity was detected in chicken spleen cell membrane. Since the capillary electrophoresis assay for ADP-ribosylarginine is simpler, faster, and less expensive than the high-performance liquid chromatography assay, determination of arginine-specific ADP-ribosyltransferase activity in animal tissues will be facilitated.
...
PMID:Assay of arginine-specific adenosine-5'-diphosphate-ribosyltransferase by capillary electrophoresis. 773 49

Turkey erythrocyte ADP-ribosyltransferase A catalyzes the transfer of ADP-ribose from NAD to both monomeric and polymeric skeletal muscle alpha-actin with the incorporation of 2 mol of ADP-ribose per mol of actin. In contrast, Clostridium perfringens iota toxin ADP-ribosylates only G-actin, with modification at arginine-177 [Vandekerckhove, J., et al. (1987) FEBS Lett. 255, 48-42]. Transferase A-catalyzed modifications are sensitive to 0.5 M neutral hydroxylamine, consistent with the arginine side chain modification. Radiolabeled peptides ADP-ribosylated by transferase A were generated by tryptic digestion and purified by reversed phase high-performance liquid chromatography. Amino acid sequence and molecular mass analysis identified the ADP-ribosylation sites as Arg-95 and Arg-372 of actin; both residues are located within subdomain-1 of the actin 3D structure [Kabsch, W., et al. (1990) Nature 347, 37-44]. ADP-ribosylation did not affect cytochalasin D-stimulated G-actin ATPase, the binding of actin to DNase I or to gelsolin, or the ability of actin to polymerize. Following ADP-ribosylation, however, a prolonged delay in polymerization was observed, consistent with a decreased rate of nucleation.
...
PMID:ADP-ribosyltransferase type A from turkey erythrocytes modifies actin at Arg-95 and Arg-372. 781 15

Bacterial toxin ADP-ribosyltransferases, e.g. diphtheria toxin (DT) and pertussis toxin, have in common consensus sequences involved in catalytic activity, which are localized to three regions. Region I is notable for a histidine or arginine; region II, approximately 50-75 amino acids downstream, is rich in aromatic/hydrophobic amino acids; and region III, further downstream, has a glutamate and other acidic amino acids. A similar motif was observed in the sequence of the glycosylphosphatidylinositol-linked muscle ADP-ribosyltransferase. Site-directed mutagenesis was performed to verify the role of this motif. Proteins were expressed in rat adenocarcinoma cells, released from the cell with phosphatidylinositol-specific phospholipase C, and quantified with polyclonal antibodies. Transferase His114 in region I aligned with His21 of DT; as with DT, the H114N mutant was active. Aromatic/hydrophobic amino acids (region II) were found approximately 30-50 amino acids downstream of this histidine. Although transferase has a Glu278-Tyr-Ile sequence characteristic of region III in DT, Glu278 was not critical for activity. In an alternative region III containing Glu238-Glu239-Glu240, Glu238 and Glu240 but not Glu239 were critical. Glu240 aligned with critical glutamates in DT, Pseudomonas exotoxin, and C3 transferase. Thus, the mammalian ADP-ribosyltransferases have motifs similar to toxin ADP-ribosyltransferases, suggesting that these sequences are important in ADP-ribose transfer reactions.
...
PMID:Conservation of a common motif in enzymes catalyzing ADP-ribose transfer. Identification of domains in mammalian transferases. 782 77

Mono-ADP-ribosylation appears to be a reversible modification of proteins, which occurs in many eukaryotic and prokaryotic organisms. Multiple forms of arginine-specific ADP-ribosyltransferases have been purified and characterized from avian erythrocytes, chicken polymorphonuclear leukocytes and mammalian skeletal muscle. The avian transferases have similar molecular weights of approximately 28 kDa, but differ in physical, regulatory and kinetic properties and subcellular localization. Recently, a 38-kDa rabbit skeletal muscle ADP-ribosyltransferase was purified and cloned. The deduced amino acid sequence contained hydrophobic amino and carboxy termini, consistent with known signal sequences of glycosylphosphatidylinositol (GPI)-anchored proteins. This arginine-specific transferase was present on the surface of mouse myotubes and of NMU cells transfected with the cDNA and was released with phosphatidylinositol-specific phospholipase C. Arginine-specific ADP-ribosyltransferases thus appear to exhibit considerable diversity in their structure, cellular localization, regulation and physiological role.
...
PMID:Vertebrate mono-ADP-ribosyltransferases. 789 51

ADP-ribosylation is a reversible post-translational modification of proteins involving the addition of the ADP-ribose moiety of NAD to an acceptor protein or amino acid. NAD:arginine ADP-ribosyltransferase, purified from numerous animal tissues, catalyzes the transfer of ADP-ribose to an arginine residue in proteins. The reverse reaction, catalyzed by ADP-ribosylarginine hydrolase, removes ADP-ribose, regenerating free arginine. An ADP-ribosylarginine hydrolase, purified extensively from turkey erythrocytes, was a 39-kDa monomeric protein under denaturing and non-denaturing conditions, and was activated by Mg2+ and dithiothreitol. The ADP-ribose moiety was critical for substrate recognition; the enzyme hydrolyzed ADP-ribosylarginine and (2-phospho-ADP-ribosyl)arginine but not phosphoribosylarginine or ribosylarginine. The hydrolase cDNA was cloned from rat and subsequently from mouse and human brain. The rat hydrolase gene contained a 1086-base pair open reading frame, with deduced amino acid sequences identical to those obtained by amino terminal sequencing of the protein or of HPLC-purified tryptic peptides. Deduced amino acid sequences from the mouse and human hydrolase cDNAs were 94% and 83% identical, respectively to the rat. Anti-rat brain hydrolase polyclonal antibodies reacted with turkey erythrocyte, mouse and bovine brain hydrolase. The rat hydrolase, expressed in E. coli, demonstrated enhanced activity in the presence of Mg2+ and thiol, whereas the recombinant human hydrolase was stimulated by Mg2+ but was thiol-independent. In the rat and mouse enzymes, there are five cysteines in identical positions; four of the cysteines are conserved in the human hydrolase.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:ADP-ribosylarginine hydrolases. 789 53

Previous studies of cholera toxin and Escherichia coli heat-labile enterotoxin have suggested that proteolytic cleavage plays an important role in the expression of ADP-ribosyltransferase activity and toxicity. Specifically, several studies have implicated a trypsin-like cleavage at arginine 192, which lies within an exposed region subtended by a disulfide bond in the intact A subunit, in toxicity. To investigate the role of this modification in the enzymatic and cytotonic properties of heat-labile enterotoxin, the response of purified, recombinant A subunit to tryptic activation and the effect of substituting arginine 192 with glycine on the activities of the holotoxin were examined. The recombinant A subunit of heat-labile enterotoxin exhibited significant levels of ADP-ribosyltransferase activity that were only nominally increased (approximately twofold) by prior limited trypsinolysis. The enzymatic activity also did not appear to be affected by auto-ADP-ribosylation that occurs during the high-level synthesis of the recombinant A subunit in E. coli. A mutant form of the holotoxin containing the arginine 192-to-glycine substitution exhibited levels of cytotonic activity for CHO cells that were similar to that of the untreated, wild-type holotoxin but exhibited a marked delay in the ability to increase intracellular levels of cyclic AMP in Caco-2 cells. The results indicate that trypsin-like cleavage of the A subunit of E. coli heat-labile enterotoxin at arginine 192 is not requisite to the expression of enzymatic activity by the A subunit and further reveal that this modification, although it enhances the biological and enzymatic activities of the toxin, is not absolutely required for the enterotoxin to elicit cytotonic effects.
...
PMID:Role of trypsin-like cleavage at arginine 192 in the enzymatic and cytotonic activities of Escherichia coli heat-labile enterotoxin. 792 84


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---